I agree that in general most want to integrate new languages with their existing code bases (rust-bindgen automatically generates C bindings, ABI tests, etc. using libclang to access C and C++ from Rust, and for each language there are tools to generate bindings and ABI tests for Rust code, e.g., the cpp crate generates C++ wrappers around Rust libraries).
The consultancy company developing c2rust specifically helps clients translate their apps to Rust. IIUC these clients want to move from C to a memory and thread safe language without loosing performance.
c2rust is the first step in that process. It mechanically translates C into "C-looking unsafe Rust".
The engineers then go and start migrating from unsafe Rust to safe Rust incrementally.
This is a long process, c2rust speeds up a small fraction of it, but most of the engineers time is spent into translating unsafe Rust into safe Rust, and then refactoring safe Rust into idiomatic Rust.
The consultancy company developing c2rust specifically helps clients translate their apps to Rust. IIUC these clients want to move from C to a memory and thread safe language without loosing performance.
c2rust is the first step in that process. It mechanically translates C into "C-looking unsafe Rust".
The engineers then go and start migrating from unsafe Rust to safe Rust incrementally.
This is a long process, c2rust speeds up a small fraction of it, but most of the engineers time is spent into translating unsafe Rust into safe Rust, and then refactoring safe Rust into idiomatic Rust.